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wizyta

od 2020-09-20

Dr Justyna Krzaczkowska  | 2002-10 <> 2007-12

Doktorant

  0000-0003-2820-3355     55183860700  

Publikacje                Magistrowie           Seminaria


6.

Strankowska J., Piszczyk L., Strankowski M., Danowska M., Szutkowski K., Jurga S., Kwela J.

Molecular dynamics studies of polyurethane nanocomposite hydrogels Polyurethane PEO-based hydrogels have a broad range of biomedical applicability. They are attractive for drug-controlled delivery systems, surgical implants and wound healing dressings. In this study, a PEO based polyurethane hydrogels containing CloisiteA (R) 30B, an organically modified clay mineral, was synthesized. Structure of nanocomposite hydrogels was determined using XRD technique. Its molecular dynamics was studied by means of NMR spectroscopy, DMA and DSC analysis. The mechanical properties and thermal stability of the systems were improved by incorporation of clay and controlled by varying the clay content in polymeric matrix. Molecular dynamics of polymer chains depends on interaction of CloisiteA (R) 30B nanoparticles with soft segments of polyurethanes. The characteristic nanosize effect is observed.

European Physical Journal - Special Topics, 222(9), 2179-2186 (2013)

DOI: 10.1140/epjst/e2013-01994-8


5.

Strankowski M., Strankowska J., Gazda M., Piszczyk L., Nowaczyk G., Jurga S.

Thermoplastic polyurethane/(organically modified montmorillonite) nanocomposites produced by in situ polymerization A series of polyurethane nanocomposites were synthesized from thermoplastic polyurethanes (with different hard segment ratios) and two types of organically modified montmorillonites (OMMT) - Cloisite (R) 10A and Cloisite (R) 20A. The thermal behavior was examined by non-isothermal thermogravimetry (TG, DTG), Differential Scanning Calorimetry (DSC) and Dynamic-Mechanical Thermal Analysis (DMTA). The results of X-ray analyses showed that the OMMT produced the intercalated polyurethane nanocomposites. It has been proven that the thermal stability and tensile properties of these new systems were higher when the organoclay was present within the polymer matrix. Moreover, these properties depend on both the OMMT loading and the type of gallery cations of the organically modified montmorillonites.

Express Polymer Letters, 6(8), 610-619 (2012)

DOI: 10.3144/expresspolymlett.2012.65


4.

Strankowska J., Fojud Z., Jurga S., Strankowski M., White J.L.

Polymer-dependent layer structures in montmorillonite nanocomposites We have studied structural differences among tetrahedral and octahedral sodium Montmorillonite layer arrangements in naturally occurring and synthetic montmorillonite clay minerals, as well as their poly(ethylene oxide) and poly(epsilon-coprolatone) polymer nanocomposites.

Journal of Analytical Science & Technology, 2(A), A22-A30 (2011)

DOI: 10.5355/JAST.2011.A22
WWW: http://www.jastmag.org/journal/view.php?number=52


3.

Krzaczkowska J., Strankowski M., Jurga S., Jurga K., Pietraszko A.

NMR dispersion studies of poly(ethylene oxide)/sodium montmorillonite nanocomposites The frequency dependence of spin lattice relaxation times measured by means of Fast Field Cycling (FFC) Relaxometry and spin locking on and off-resonance NMR techniques were used to study the molecular dynamics of poly(ethylene oxide) polymer in the confined and bulk phases of PEO/MMT nanocomposite systems. The Rouse model, the renormalized Rouse formalism and the concept of reptation were applied to describe the polymer behavior in the samples studied. The polymer dynamics was found to depend on the molecular weight of the polymer intercalated in the clay structure. Analysis of the NMR T(1)(nu) profiles allowed discrimination of the molecular dynamics of polymer chains at different locations in the nanocomposite structure. Two components of the T(1) spin-lattice relaxation times were indicated for low molecular weight PEO polymers using the FFC method. The longer one was connected with the bulk polymer, whereas the shorter one was attributed to the intercalated polymer fraction. Analysis of the correlation times indicated that polymer confined in montmorillonite galleries is more rigid than that in the bulk phase. To determine the two phases of the polymer for the high molecular weights polymers, additional methods were applied: spin locking, off-resonance NMR techniques and inversion-recovery experiment at a static magnetic field.
(C) 2010 Elsevier B.V. All rights reserved.

Journal of Non-Crystalline Solids, 356(20-22), 945-951 (2010)

DOI: 10.1016/j.jnoncrysol.2010.02.005


2.

Krzaczkowska J., Szcześniak E., Jurga S.

Phase behaviour of dipalmitoylphosphatidylcholine/surfactant/water systems studied by infrared spectroscopy Phospholipids are the most important components of membranes taking part in stabilization of the functional structure of biological cells. The main aim of the present study is to determine the influence of selected antimicrobial surfactants on the phospholipids structure. The water solutions of dipalmitoylphosphatidylcholine (DPPC) in the presence of two quaternary ammonium surfactants: dodecyidimethyl(hexyloxymethyl)ammonium chloride (HMDDAC) and (decyloloxymethyl)dodecydimethylammonium chloride (DMDDAC) were studied using FTIR spectroscopy. The thermal behaviour of these systems was analyzed using spectral parameters of CH2 and C=O vibrations bands. We have observed a lowering of temperature corresponding to the main phase transition of the surfactant/DPPC systems due to disordering of the phospholipids structure by the surfactants and phospholipids interaction.
(C) 2006 Published by Elsevier B.V.

Journal of Molecular Structure, 794(1-3), 168-172 (2006)

DOI: 10.1016/j.molstruc.2006.02.003   (Pobrane:  2020-10-21)


1.

Krzaczkowska J., Fojud Z., Kozak M., Jurga S.

Spectroscopic studies of poly(epsilon-caprolactone)/sodium montmorillonite nanocomposites Polymer-layered silicate nanocomposites belong to a new class of hybrid materials consisting of organic-synthetic polymer matrix and inorganic filler-layered structure clay minerals. The paper presents the results of FTIR, NMR, and SAXS studies of poly( epsilon -caprolactone)/sodium montmorillonite nanocomposites. We observed a correlation between the concentration of poly( epsilon -caprolactone) in nanocomposite samples and structural changes both of the clay mineral and the intercalated polymer. Stiffening of the clay structure appears as a result of poly(epsilon -caprolactone) intercalation into a clay structure. 27Al NMR studies indicated in nanocomposites two non-equivalent sites of aluminium ions, i.e. in octahedral and tetrahedral coordination, whereas in the montmorillonite clay structure the aluminium ions are located in the interlayer space too. We found also that the temperatures of structural changes and softening process of poly( epsilon-caprolactone) chains in the nanocomposites depend on the concentration of poly( epsiv -caprolactone).

Acta Physica Polonica A, 108(1), 187-196 (2005)

DOI: 10.12693/APhysPolA.108.187
WWW: http://przyrbwn.icm.edu.pl/APP/PDF/108/a108z124.pdf   (Pobrane:  2021-01-10)


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